[FFmpeg-devel] [PATCH 2/2] avcodec/imm4: Unreference previous frame on frame size change

[Paul B Mahol]

On 3/10/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> Fixes: Out of array access
> Fixes:
> 13552/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IMM4_fuzzer-5767949648920576
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/imm4.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/libavcodec/imm4.c b/libavcodec/imm4.c
> index b66689acab..1a4d0decd7 100644
> --- a/libavcodec/imm4.c
> +++ b/libavcodec/imm4.c
> @@ -446,11 +446,13 @@ static int decode_frame(AVCodecContext *avctx, void
> *data,
>          return AVERROR_PATCHWELCOME;
>      }
>
> -    if (!frame->key_frame &&
> -        (avctx->width != width ||
> -         avctx->height != height)) {
> -        av_log(avctx, AV_LOG_ERROR, "Frame size change is unsupported.\n");
> -        return AVERROR_INVALIDDATA;
> +    if (avctx->width  != width ||
> +        avctx->height != height) {
> +        if (!frame->key_frame) {
> +            av_log(avctx, AV_LOG_ERROR, "Frame size change is
> unsupported.\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +        av_frame_unref(s->prev_frame);
>      }

ok